ANODISING SUPPORT

Anodising at home can seem daunting, especially when you see some of the flawless finishes produced by large industrial finishers. Fear not, we have you covered! In this section of the website we will guide you through the entire process, from deciding what setup you need to setting up the kit and anodising items. 

Check out the menu list below to skip to the section that you need.

 

1. What Is Anodising?

The principle behind anodising is the expansion of the natural oxide layer which forms on aluminium parts using direct current through a solution called an electrolyte. The extra oxide growth gives excellent corrosion protection and leaves the surface ready to accept dyes. 

2. What Supplies Do I Need?

The tools required for anodising can be broken down into essentials and extras. These items (except water) are conveniently measured and supplied in our kits. 

 

Essentials:

  • PPE: gloves, goggles, mask

  • Anodising tank: PP or HDPE plastic or glass

  • Anodising chemicals: sulphuric acid, anodise stripper and etch

  • Water: distilled, deionised or pure water (not tap water)

  • Electrical connectors: wires, copper wire, bus bar

  • Power Supply: 0-15V, 0-5A, adjustable

  • Cathodes

 

Extras:

  • Tank Heater

  • DeOx/DeSmut

  • Cold Sealer

  • Dyes

  • Electrolyte Filter

  • Electrolyte Agitator

  • Rinse bottle

  • Extra Tanks

  • Extractor Fan

 
 

3. How Do I Keep Myself Safe?

The absolute most important aspect of the entire electroplating process is safety. Please, please, please do not skip or miss any safety steps. Doing so, either at the beginning of your electroplating journey, or during, may cause serious harm to yourself or others. If you have been electroplating for quite some time, please do not get complacent as safety should be and is always the most essential step to follow. 

 

The absolute minimum safety precautions needed for electroforming are; PPE, adequate ventilation, a safe electroplating area, neutralising solution and an undisturbed space. 

Hazards & Risks

The main sources of risk, hazards, associated with electroplating are the chemicals in the electrolyte and the electrical circuit. 

Material Safety Data Sheets (MSDS) can be downloaded from our website or from different online sources. These give a clear and concise description of the chemicals and their associated hazard identification.

PPE

Gloves should be worn at all times! Not only will wearing gloves protect your hands from potential chemical exposure, but it also prevents the spread of contaminants onto your items and into the electroplating tank. On a personal note, we would advise again disposable and single use gloves as they have a negative impact on our world and environment.

Goggles should be worn whenever chemicals or electrolyte are in use. This includes initial mixing, filtering, maintenance, rinsing and especially when placing items into and removing items from the electroplating tank. 

The main function of masks is to protect your airways; your mouth, nose and throat. Masks should be used at the time time as goggles; initial mixing, tank filtration, etc. They should also be used when the ambient room temperature is lower than that of the tank. When this temperature difference occurs, liquid will evaporate from the electrolyte with the potential to take other chemicals with it. A mask should also be used when painting with solvent based paints or sealers. Finally, if the environment in which electroplating does not have adequate ventilation or if there is no direct extraction masks should be worn.

Safe Environment

Creating a safe environment to electroplate in is important in regards to keeping yourself and others safe.  One thing to consider before setting up your own tank is where it will be placed. Having the electroplating system in your house is not advised unless you have all of the safety precautions in place.

 

Below is a list of questions and advised answers to help think and setup an ideal electroforming area.

  1. Will you be electroplating inside your house or outside in a shed/workshop/garage?

  2. Is there already a clear space to electroplate in?

  3. Is there any form of ventilation already? (e.g. doors, windows or extractor fan)

  4. Will your electroplating area be disturbed?

  5. Is there anything close that will be affected by fumes or accidental splashes?

4. How Do I Set Up The Kit?

For full instructions on how to setup the kit, including electrolyte mixing, follow the instructions included with the kit. 

 

As a general guide, the workflow for setting up a 5L kit should be:

  1. Add 5L of diluted sulphuric acid into a container

Stripper and Etch:

  1. Add 4.5L of distilled water into a container

  2. Add and dissolve stripper and etch salts

  3. Top up to 5L

DeOx/DeSmut

  1. Empty solution into container

  2. Dilute until the required volume percentage has been achieved

  3. mix well

Anodal Cold Sealer:

  1. Add anodal powder into tank

  2. Add water to achieve 5 g/l

  3. Mix until dissolved

Hanging the Cathodes

Cut about 600mm off the copper wire and thread through the hole in a lead cathode and twist together the end of the wire  to secure the anode. At the opposite end of the copper wire attach the other lead cathode. Next, hook the anodes over the lip of the tank making sure the copper wire that is attached to the anodes is above the level of the electrolyte or copper will be leached into the electrolyte and ruin the electrolyte. Place the lead cathodes opposite each other on inside of the tank. Run the copper wire under the rim, on the outside of the tank to secure it. Make sure that you remove the cathodes form the tank, rinse them well and place them in a clean container if you are not 

going to be anodising for some months.

Wiring the Circuit

Once the cathodes are secure in the tank, you can begin to assemble the rest of the circuit. First, strip both ends of the blue  and brown wire to expose the internal copper fibres. Attach one end of the blue wire to the negative terminal of your power source, the opposite end of the blue wire should be attached to the copper wire connecting the lead cathodes. One end of the brown wire should be attached to the positive of your power source, the other end should be attached to the aluminium wire that the part you want to anodise is attached to.

 

Tank Accessories

It can be useful to use a tank heater to get the anodising tank up to 19°C which is the ideal temperature to start the anodising  process off at. If you are using a tank heater, insert it into the electrolyte so that the glass is fully submerged. If any of the glass is out of the electrolyte, then the thermal expansion as it heats and cools may cause the glass to crack and break; leading to electrical hazards. Make sure the tank heater is always cool before removing it from the tank. Never switch it on when it is not immersed in liquid. Agitation can be beneficial to the anodising process it is not necessary but when anodising larger items at high currents it can help reduce the chance of burning. An internal circulation pump and tank filter can be used to provide agitation. 

 
 

5. Pre-Anodising

Stripping

On items that have previously been anodised the existing anodised layer will have to be removed. This is done with the stripper and etch see details later on in this guide.

 

Cleaning

The most important part of the anodising process, after safety, is cleaning and part preparation. The importance of cleaning  cannot be understated. The cleanliness of a part will dictate which cleaning methods will be used before anodising. It is worth spending as much time as possible cleaning a part ready for anodising as soils that have not been removed from the surface will reduce the quality of the anodised layer and may even damage the electrolyte making it unusable. 

The steps in cleaning are:

  1. Remove thick oil and grease with a degreaser

  2. Remove oxides mechanically; sanding, buffing or polishing

  3. Remove any polish or cleaning residue with a solvent

  4. Remove solvent traces with detergent and hot water

  5. Rinse well

  6. Immerse in Anodise Stripper and Etch (guide included at end)

  7. Rinse in very clean water

  8. Remove any black smutting (depends on grade of aluminium) - remove with Hyperbright de-ox de-smut (instructions for use at rear of guide)

  9. Rinse well

Remember to always wear gloves during the cleaning process. Not doing so will introduce more soils which will require more cleaning. 

 

6. Anodising

Now that your part is cleaned, it is ready to anodise! The best thing to do first would be to do a practice on an item that is not critical, and you can make mistakes with. Before anodising it is advisable to find a piece of metal to span the top of the anodising tank to hang items from. This will allow you to hang your items in the centre of the tank which will give the best results. Having an item near to one cathode can cause problems and faults with the result.

 

Basic anodising process on prepared aluminium is as follows:

  1. Prepare item as per section 2

  2. Connect item to circuit very securely using aluminium wire and immerse in electrolyte

  3. Anodise using settings below

  4. Rinse well

  5. Dye (optional)

  6. Rinse 

  7. Seal

 

So, once you part is cleaned you can follow this process above. Connect the parts of the circuit as per the diagram in the previous sections. That is, the positive (+) terminal of a car battery, old type battery charger or variable DC power supply to the item to be anodised. Then attach the negative (-) terminal to the lead cathodes. Once the circuit is complete, immerse the part in the electrolyte.

 

Before turning on a variable power supply, make sure that the amperage is set to zero and the voltage is set to maximum. Now turn on the power and steadily increase the amperage. The voltage should be between 12 – 24 volts. The best way to work out the settings needed is to use a 720 calculator, there various ones available online.

If you look closely there will be tiny bubbles forming on the lead cathodes, you may even see tiny bubbles on the item you are anodising. After a few minutes you may see a slight change in the parts as an oxide layer begins to build. This process can take anywhere from 20 to 120 minutes depending on the thickness required and the speed of anodising. 

 

The temperature of the anodising tank is crucial! Always anodise as close to 20°C as possible. This ensures that the pores produced in the anodised layer are of uniform size and will take and hold dye easily. Temperature’s that are too high and too low will produce large pore size and small pore size which can lead to softer layers with large pore size that do not hold dyes well or small pores that are harder but will not take in dyes well.

 

Different finishes can be achieved with this anodising kit through manipulation of the settings, cleaning and preparation, and the time in the electrolyte. To achieve a bright and glossy finish, items should be buffed and polished before anodising, followed by a short etch and a short time in the anodising tank. For a matte finish, there is no buffing or polishing required, and the times in the etch and anodising tanks should be increased.

Now that your part has been anodised, turn off the power, remove from the electrolyte and rinse in clean water.

 

7. Post-Anodising

As with every step of the anodising process, wearing the correct safety gear in critical! Once you part has been anodised and rinsed you can now apply any number of finishes. The most common finishes are dyes and sealers. We have a large range of industrial anodising dyes and instructions on their use are supplied with the dyes themselves. Similarly, we have an industrial anodising sealer, Cold seal CS3A which is included in this kit, the instructions for its use are further on in this guice.

 

Another method to seal an anodised part is immersion in hot water, 90°C for 30 minutes. This may be used in some circumstances but it will not give as good a seal as the Cold Seal CS3A.